Ruby objects and no dup-ing.

Got to remember that when you pass an object to method, that the object is still the same object in memory and it change the object in memory changes, leading to potentially unexpected behaviour. So if you really need to manipulate the arguments a method receives, perhaps think about call blah.dup to clone it before you make changes to it.

options = { :node => 'MyNodeThing' }

def url(options)
  node = options.delete(:node)
  puts node
end

url(options)

puts options[:node]
#=> nil